Astro-Physics 1200GTO German Equatorial Mount

The Astro-Physics 1200GTO is an excellent choice for 12.5 to 16 inch RCOS Ritchey-Chretiens.

Astro-Physics 1200GTO German equitorial mount.

RCOS is an authorized Astro-Physics dealer.

With the advent of the CCD camera, amateurs are exploring the skies to an ever increasing level of precision, easily exceeding the image quality of large observatories using film techniques decades ago. This new level puts a higher demand on the precision of the equatorial mounting. Many of the finest imagers today have been using Astro-Physic GTO mounts as a solid platform for a wide variety of instruments. The largest of these is the 1200GTO.

Since its introduction in 1998, the 1200GTO has gained a reputation for both tracking and pointing accuracy, essential to casual visual observation as well as advanced imaging. Quite a few 1200GTO and 900GTO mounts can be found at Mount Pinos in California, favorite observing site of many advanced photographers and imagers.

These mounts are truly a marvel of engineering - maximum strength and rigidity with minimum weight. Astro-Physic's CNC lathes and mills carve out the excess material in both axes of the 1200 and 900 German Equatorials while retaining a heavily ribbed structure for internal strength and rigidity. A unique dovetail was machined into the mating surfaces of the R.A. and Dec axes. This feature allows quick and easy assembly in the field without any tools.

The 1200 equatorial is equally at home in a permanent observatory or as a portable mounting for remote star parties thanks to the ease with which the two axes come apart. You CAN have it all. This is the perfect mount for a large refractor, Newtonian, Cassegrain or astrograph. Telescopes commonly used include Astro-Physics 155-206mm refractors, 12-14" Schmidt-Cassegrains and 10-16" Ritchey-Chretiens.

The 1200GTO mount is built from the ground up to be a precision imaging platform while still being totally user friendly. Consider these advantages and features:

Flexibility

Portable. Extremely solid, rugged, high payload mount, yet comes apart in two reasonably light-weight components for hassle-free field setup. No tools needed to assemble the mount in the field.

Operate with 12V battery. You can take it to the darkest skies and power it with a commonly available 12V battery. In the observatory, a 5 amp filtered, regulated power supply is suggested.

External computer not needed. The keypad is a handheld computer with all of the features, functions and databases you need to tour the universe night after night. The unique software allows you to precisely polar align your mount in the field, even in broad daylight! The vacuum-fluorescent display with a temperature range of -40 degrees F (and C, they are the same in this instance), allows hardy observers to use this mount on cold winter nights. You can't do that with a PC!

Separate computer control. All functions of the servo drive can be commanded from a laptop or desktop computer using popular planetarium software. Depending on the features of the program, you can position your telescope, center your image and control tracking rate, remote focusing, reticle brightness and park at the end of your observing session. Examples of currently available software:

Write your own computer program. The Astro-Physics GTO protocol is freely available to those who would like to write their own computer program for controlling the mount. While based on the Meade protocol, it has many more features and enhanced precision level which allows pointing and tracking to the 1 arc second level.

Precise Mechanical Fabrication

Highly accurate mechanics. Using modern CNC machining techniques, Astro-Phyics makes all components to a high precision level which results in a final package that is solid and accurate in all respects. The critical angles are accurately machined so that the mount is orthogonal to a very high degree. This results in pointing accuracies well below 1 arc minute for a properly aligned mount.

Worm gear accuracy. Critical worm gear accuracy is maintained by special machining techniques developed at Astro-Physics after extensive studies and actual field operation. Astro-Physic's worm accuracies are second to none. With good alignment and PEM training, it is quite practical now to achieve unguided CCD images with today's hi-resolution cameras coupled to a 6" to 16" telescope.

Mechanical Features

Servo Motor Drive

The drive system uses a high-quality zero-cogging DC servo motor controlled by a microprocessor to an accuracy of 0.05 arc seconds per step. Tracking is very smooth, noticeably smoother than any stepper motor drive or inexpensive servo drive. The system can be accurately controlled over a speed range of 4800:1 which allows 0.25x sidereal for guiding to 1200x sidereal for 5 degree per second. The circuit draws only 0.4 amps when tracking the stars, 2 amps with both motors slewing and requires only 12 volts to operate. This servo drive will satisfy the requirements of the sophisticated, advanced astrophotographer, yet is easy for the casual, visual observer to use.

DigitalSkyVoice™ Software

DigitalSky Voice is a terrific observing companion offering lots of observing ideas and information. If you plan to use an IBM-compatible personal computer to control your telescope, you will have lots of fun with this program. The software is included with the mount.

1200GTO Specifications
R.A. worm wheel 10.3" (26.2cm), 225 tooth aluminum
Declination worm wheel 7.2" (18.3cm), 225 tooth aluminum
Worm gears Brass
R.A. thrust bearings 9.5" (24.1cm) diameter
Declination thrust bearings 6.5" (16.5cm) diameter
R.A. shaft 3.35" (8.5cm) diameter
Declination shaft 2.36" (6.0cm)diameter
Latitude range 20 to 68 degrees
Azimuth adjustment Approximately 14 degrees
Setting circles Porter Slip Ring design, engraved
Right ascension 4 minute increments, pointer, engraved both Northern/Southern
Declination 1 degree increments, pointer
Capacity 140 lb. (63.6kg) instrument, depending on length
Weight of equatorial head 91 lbs. (41.4kg), Dec axis is 30 lbs. (13.6kg) , RA axis is 47 lbs. (21.4kg), counterweight shaft is 14 lbs. (6.4kg)
Software DigitalSky Voice™

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